Spark-plug.



U. U. E LDRIDGE & E. J. BEEBE. SPARK PLUG.

APPLICATION FILED MAR. 20, 1911 1,028,200, I Patented June 4,1912. v

UNITED STATES PATENT OFFICE.

CHARLES C. ELDRIDGE AND EDWIN J. BEEBE, 0F MARSHALLTOWN, IOWA. I

SPARK-PLUG.

Patented June 4, 1912.

Application filed March 20, 1911. Serial No. 615,689.

To all whom it may concern Be it known that we, CHARLES C. ELDRIDGE and EDWIN J. BEEBE, citizens of the United States, residing at Marshalltown, in the county of Marshall and State of Iowa, have invented certain 'new and useful Improvements in Spark-Plugs, of which the follow ing is a specification.

Our invention relates to improvements in spark plugs of the eneral type disclosed in a former application No. 606,47 7 filed February 4, 1911, by Charles F. Johnston, and has for its principal objects to provide an improved construction of the electrode tips for producing a more powerful spark, and also to provide ready means adapted to facilitate adjusting and cleaning such electrodes. These and further objects will be made apparent in the following description and claims taken in connection with the accompanying drawings in which like reference numerals refer to like parts.

Figure 1 is a front elevation of the spark plug assembled complete. Fig. 2 is a vertical axial section of the plug along the line 22 of Fig. 3. Fig. 3 is an enlarged upward plan view. Fig. 4 is an enlarged front elevation of the lower end of the spark plug with the gage and cleaner element engaging the electrodes, said element being shown in axial section. Fig. 5 is a transverse plan view taken on the line 55 of Fig. 4 facing withthe arrows.

The main body 1 of our improved spark plu comprises chiefly a bushing-likc casing 2 a apted to bescrewed into an engine cylinder, an insulator 3 contained therein, and a nut 4 locking said insulator in position within said casing. The insulator 3 is'provided with an annular flange 3, one side of which bears against a suitable packing ring 5 resting on the, shoulder 2' of the casing 2. The other side of this flange 3 is engaged by the inner end of said nut 4. The insulator 3 is hollow and contains an electrode rod 6 and the annular shoulder formed by the restri'cted opening in the insulator which'extends upwardly from the petticoat 3. Surrounding the rod 6 within the lower portion of the petticoat 3 is an additional quantity of cement 19 or the like which assists by its cushioning action to preventbreakage of the insulator 3 by the expansion of the electrode 6. The upper end of the rod 6- is threaded and provided with a nut 10 beneath which and the upper end of the insu-v lator 3 is a suitable washer 11.

The extreme outer end of the rod isprovided with a cap 12 to facilitate the attachment of an electric wire, said caphaving a relatively large threaded axial hole 13 in its lower portion to receive the end of the rod 6 and a small cylindrical perforation 14 extending axially through its upper tip end. The upper end 15 of this cap is formed externally in the shape of a small cylinder coaxial with the main body of the cap. This small cylindrical portion .is provided with an annular series of radially extending points 16. Below the portion 15 is the body part 17. The opposite or lower end of the plug is provided with a plurality of electrode elements or branches 20 which extend outward parallel with the central electrode 18 for a short distance and then turn inward at points 21, the inwardly turned portions 22 being preferably inclined diagonally toward the central electrode 18. The inner ends of these branches preferably all he in .a common plane extending transversely of the central electrode. They are provided on their inwardly turned end faces with notches extending in the present embodiment transversely of the axis ofthe plug and are provided on the edges of said notches with corresponding inwardly turned points lying adjacent to but slightly out of contact with the centrahelectrode. These pointspermit the sparks to jump more easily between the electrodes.

If the electrode branches 20 should become bent so as to be unequally distant from the central electrode, the cap 12 maybe unscrewed from the rod or binding post 6, the end 15 of said cap inserted over the central electrode 18, and tips 22 pressed into con tact with the portion 15 of the cap. It will thus be seen that the cap 12 may be used as a gage when the electrodes require adjustment. Should the electrodes become corroded or coated with carbon, the cap 12 may be placed upon the central electrode 18 as above described, with the points 16 lying be tween the tips 22'. Tlhe cap may then be turned, the points 16 passing through and engaging successively the several notches aforesaid, thus cleaning and polishing them.

described our invei'ition, we

therefrom by a suitable spark space.

2. In a spark plug, in combination, amain body portion, a central electrode extending outward from one end thereof, and a second electrode having a plurality oi? branches extending outward from said body at the sides of said central electrode, the free ends of said branches being turned toward the said central electrode and each being provided with a transverse notch and a pair of corresponding points on the opposite sides of said notch, and means detachable from the opposite end of said body adapted to fit rotatably on the said central electrode as an axis to facilitate adjusting and cleaning said electrodes.

3. In a spark plug, the combination with abody having a central axial electrode on one end, of a second electrode having branches, the free ends oi which are turned toward the said central electrode and each of. said branches-being provided with trans verse notches and points on opposite sides of said notches, and a detachable cap on the other end of said bodylthe outer end of Which is longitudinally perforated along its axis enabling it to fit o'verthe said central electrode and also provided With an annular row of radially extending points adapted to successively brush pastthe several notches aforesaid when the said cap is rotated on the said central electrode as an axis to clean the said electrode.

A spark plug of the character described, comprising a plurality of electrodes one of which is notched, and. an clcn'icnt adapted. to be detached tron'i the plug and having a perforationadapted to be fitted rotatably u pon one of the electrodes of the plus, said element also having a [)I'OjUClLlO D adapted to brush pastthe notched electrode, said projection passing through the notch to clean the latter when said elcn'ient is retated upon the first mentioned electrode.

5. In a-spark plug oi the character'described, a main body portion and electrodes on one end thereof, one oi said electrodes being notched, and a detachi'rblc cap having a longitudinal axial perforation adapted to receive one electrode, a cylindrical portion of said cap coa"'al with said perforation adapted, when pivoted on said electrode, to serve as a in adjusting;- the distance of the notched electrode, and a radial member on said cylindrical portion extending at a angle to said perforation and adapted to brush past the notched electrode andenter the notch to clean it "when the said cap is rotated on the liI'Si electrode.

6. in a spark plug of the character as scribed, the combination of a casing, an insulating sleeve therein, a central electrode in the form of a rod lying Within said sleeve, an enlargement on said rod adjacent one end of said sleeve, packiiig'inatcrial surrounding; sai i rod between said enlar ement and the adjacent portion of said sleeve,

means at the opposite end oi said rod for drawing said ei'ilargeinent against said packing and holding the electrode inthc sleeve, a pctticoat upon one endiof said sleeve sun rounding said packing and said enlarge-' rnent, quantity or cement surrounding said electrode Within said sleeve at the side of said enlarc'emcnt opposite said. packing, and a coating oi cement surrounding said electrode, and ext-ending from said packing to the opposite end or said sleeve.

lin testimony whereof. \ve aiiiz; our signa tures in presence of two Witnesses.

Witnesses:

n i. i n 

